Since then, with the advance of computing environment, various Internet services are emerging and the importance of user authentication technology is increasing for verifying users authorized to use such services. Along with the advance of authentication technology, research is being made actively on one time password, which is used once in a session and then discarded. In existing one time passwords, however, the values of one time passwords in a created table are stored in serial order, and therefore, if the seed value and the number of one time passwords used are disclosed, one may infer the value of the one time password to be used next. What is more, one time passwords of the S/Key type have the problem that the number of uses is fixed. In this paper, We analysis the existing one time password. Also, We propose one time password methods using elliptic curve cryptography scheme and using enhanced randomness with time value.